meson: doxygen support wip

meson.build

@@ -194,7 +194,13 @@ if doxygen.found()
     output: 'Doxyfile',
     configuration: doxygen_data,
     install: false)
-  run_target('doc', command: [doxygen, doxyfile])
+  doc_dir = join_paths(get_option('datadir'), 'doc', 'libdsm')
+  run_target('doc',
+             command: [doxygen, doxyfile],
+             input: doxyfile,
+             output: 'html',
+             install: true,
+             install_dir: doc_dir)
 else
   warning('Doxygen not found - continuing without Doxygen support')
 endif